Signaling system



Emmy R. 0, SOFFEL SIGNALING SYSTEM Filed Deo. 29, 1955 ouT PuL s/A/ ai/Rcu/ T Patented July 16, 1935 PATENT orties N i SIGNALING SYS'IEll/I `Robert 0. Soffel, Hastings-upon-Hudson, N. Y.,

,assignor to BellTelephorxe Laboratories, Incorporated, New York, N Y., a corporation of New York Application December 29, 1933, Serial No; '794,371

` 12 claims.V (ci. 1794-16) This invention relates to telephone systems and more particularly to the utilization inthe'impulse recording circuits thereof of gaseous conductor or discharge tubes as impulse responsive relays.

In machine switching telephone systems, the impulsesdialed by a subscriber or by an operator may control the setting of selector switches directly as,` for example, in the well known systems employing'step-by-step type selector switches, or to control the setting of digit registers 'asin sys-1. tems employing 'central oiiice senders,l a's,'for example, in the wellknown panel or directorY type` systems. In order that proper response to `dialing impulses may be obtained over both long and.

15 short dialing loops, it is essential. that the i1.

pulse responsive apparatus shall be very accurately'adjusted and sensitive.

It is therefore'the object oi' the invention to provide an impulse responsive device whereby more accurate and faster impulse Vresponsel may be realized over long dialing loops.

In accordance with the present invention a gaseous conductor or discharge tube is utilized to respond to dial or othersources of impulses and to in turn control an impulse responsiverelay. The impulse responsive relay may, as desired, control the stepping magnetJ oi a selector switch, an impulse repeater or control apparatusior recording the dialed impulses. The gaseous discharge U cenductor tube employed is a tube sued with a.

low pressure gaseous content which, for purposes of' illustration, might be neon, argon, helium, mercury vapor or combinations of gases of this group. 'The tube has a certain characteristic, namely, that the gaseous content will become ionized and thus conducting `on one potential determined by the electrode design, the nature of the gaseous content and its pressure, but once rendered conducting will maintain this condition of conductivity on a much lower potential. The

tube may be of the hot cathode type having a iilament heated by a direct current source of potential or having a cathodeheated conductively from a filament" energized from a source of alternating or direct current cr may be of the cold cathode type.

T'he invention has been disclosed in connection with both hot and cold cathode `types'of tubes.

Considering brieiiy the embodiment `ci the invention using a tube of the hot cathode type, the

dialing loop, disclosed for the purposes of illustration as extended through a subscribers substation, is connected inductively by a transformer to the grid and cathode-anode circuits of a gaseous conductor tube. The anode of y receiver from the switchhook, current flows over the dialing loop through the primary winding of the transformer, `thereby causing surges of potential in the two secondary windings whichare connected respectively tothe grid and cathodeanode circuits of the tube. windings are so poled with respect to the primary winding that the surge of potential through the secondary winding connected to the grid, which results fromlthe closure of the dialing loop, makes the bias on the grid of the tube less negative and the surge of potential through the secondary windingV connected tothe anode, which results from the closure of the dialing loop, places positive potential onfthe anode. ,The tube will now become conducting thereby .operatingthe impulse responsive relay over the cathode-anode `circuit of the tube to prepare .the outpulsing circuit. The outpulsing circuit may extend to any type of ap-` paratus which is to be operated in response to incoming impulses such, for example, as the stepping magnet of a selector switch, an impulse repeater or the recording apparatus of a sender.

When the dialing loop is now opened as by the opening of the contacts of the substation dial, surges of potential are produced in the secondary Vwindings of the transformer but in directi'ons opposite to those induced upon the closure of the dialing loop. The surge through the secondary winding connected to the grid now increases the negative bias of the grid and the surge' through the secondary winding connected to lthe anodev now reduces the positive potential on the anode tof such a degree that ionization of the tube ceases "and the impulse responsive re-` lay releases` to transmit an impulse to the outpulsing circuit. Upon subsequent reclosures and' openings of the dialing loop, the tube becomes conducting and deionizes in this manner to cause the operation and release of the irnpulse responsive relay'to transmit further impulses to the outpulsing circuit. Since the tube responds quickly to changes or" potential only and not to current build up, as is necessary when a relay is employed to respond directly to dialing impulses, impulsing may be accuratelyaccomplished over either shorter long dialing loops and at muchgrcater speed.

Further, since the The two secondary ment the positive terminal of the central oflice battery is Vconnected through one secondary winding ofthe transformer tooneY of the cath- Vodes of the tube, the other cathode .being connected to the negative terminal of central oilice battery and the positive terminal of battery is connected through the other secondary winding of the transformer and the winding `of the impulse responsive relay to the anode of the tube. With the dialing loop normally opened,the tube is in a quiescent or non-conducting condition. When the dialing loop is now closed the surges of potential thus resulting through 'the secondary windings of the transformer will increase the positive potentialY on both the rst or control cathode of thetube and on the anode and the'tube willfbecome conducting to operate the impi'ilse'responsive relay, Upon the first opening of the dialing loop by the dialing contacts or other impulsing means, surges of potential 'n thus resulting through the secondary windings,

now being in the opposite direction from those resulting from the closure of the dialing loop 'will' decrease' the positive potential on the rst cathode and on the anode to such an extent that the tube will deionize and release the impulse responsive relay.

` ing Vin which:

Figi shows one embodiment of the invention including a subscribers substation, dialing loop,

hot'cathode gaseous conductor tube and impulse responsive apparatus; and

Fig. 2 shows a second embodiment ofl the invention including a subscribers substation, dialing loop, cold cathode gaseous conductor tubo and impulse responsive apparatus.

Considering iirst the embodiment of the invention illustrated in Fig. l, the subscribers substation lll having a substation dial llll may be extended in any well knownmanner to the central oilice apparatus which is to be controlled therefrom. At the central olice one conductor of the subscribers dialing loop terminates in the grounded or positive terminal of the central oice battery and the other conductor of theY loop extends through the primary winding P of a transformer lll to the negative or ungrounded terminal of battery. The transformer IBI has two secondary windings one of which S is included in a path between the control electrode or grid of tube 02 and the negative terminal of battery and theV other of which S2 is included in a path extending from the anode of the tube through the windingof impulse responsive relay les to the positive terminal of battery. The cathode of the tube Vis connected through resistance HM to thel negative terminal of battery and is heated by conduction from the'lament of the tube. over a circuit extending from the negative terminal'of battery through resistance |64, through the lament and resistance |05 to ground. Resistance m6 is connected in parallel with the fila- Vment and the serially connected resistance |05.

The filament of the tube is lighted p Thus normally with the dialing loop open, the grid of the tube is so negatively biased that the tube is quiescent or non-conducting.4

When the subscriber removes his receiver from the switchhook the dialing loop is completed in the well known manner and current then flows over the loop through the primary winding P of transformer I 8| resulting in the establishment of surges of potential in the secondary windings S and S2 of the transformer. The secondary windings are so poled with respect to the primary winding that the surge through secondary windof the tube now results in making the tube conductive whereupon space current ilows from the negative terminal of battery through resistance |Il4 o-ver the cathode and anode of the tube with the number of digit impulses which he. de-- sires to transmit and then permits the dial to,

return to normal.` As the dial returns to normal it intermittently opens the dialing loop. Y Upon Vthe first Vopening of the dialing loop, current ceases to'flow momentarily through the primary winding P of transformer l0! thereby producing surges of potential in the secondary windings thereof which are opposite in` direction to the surges produced upon the initial closure of the dialing loop. The'surge in secondary winding S now increases the normal negative bias on theV grid of tube @I and the surge in secondarywinding S2 decreases or substantially nullilies the positive'potentialon the anode of the tube. The ionizationof the tube can not now be maintained and current ceases to dow over the cathode-anode circuit through the winding of relay |03. Relay |03 releases but relay |08 being slow to releasedoes not release and therefore an impulse is transmitted from groundover the back contact of relay |33, front contact of relay |08 overroutpulsing circuit |09 to the apparatus which is to be operated. This apparatus may, as previously indicated, be a selector switch, impulse repeater or any desired recording mechanism such as the recording mechanism of a central oflice register sender.

' On the next closure of the dial contacts, theV dialing loop is again closed thereby causing surges in the secondary windings S and S2 of the transformer Illl which result, as previously described, is causing the tube |32 to' again become conducting and operate relay |03. Relay |03, upon reoperating, reestablishes the circuit of relay |08 and opens the outpulsing circuit |99 to terminate the :drst impulse transmitted thereover. In response to subsequent openings and closures Vof the dial contacts or until the dial reaches its normal position, the tube |02 responds to cause the intermittent release and operation or relay |03 to transmit further impulses to the outpulsing circuit !99. Upon the termination of the digit series of impulses, the dialing loop is maintained closed until the next series of impulses is dialed and the tube m2 therefore remains conducting to hold relays |3 and |88 operated. Change over for recording the next series of impulses dialed may be CII '03"' to transmit Tfurther impulses to the outpulsinglcircuit-i09'.

\ The circuits illustratedin Fig. 2 are Asirnilarfto` those of'Fig; 1f Withtheexception that-a` cold,-I cathode type' of' tube |02" is employedrequiringf accomplished byfapparatus f associated with i outpulsingfcircuit lll'inthe usualmanner. A

slight'alter'ations in the circuits for associating it'fwith the windings lofi the transformer; OneV cathode' of the tube is connecteddire'ctlyto theA negative terminal of central ofce battery" and the other or controlcathoide is connected'to the positive or grounded'terminal oflbattery through resistance iii!" andthe secondary windings ofI transforrryieililll; The' anode of` the-tube iscon-l nected to the positive terminalof'battery throughl the winding of impulse responsive relay |03 and' the secondary Winding S2 of r'transformer' 10|. With the dialingloop--normallyopen; the tubeis in a-quiescent condition sincethe difference of potential'between the cathodes of the tube is in n and the tube becomes conductive, whereupon spacecurrentilows from thenegatlve terminal of battery over the lower cathode and the anode of-the'tube' through the'windin'g'of relay |03r andi theV secondary windings2 of the transformer to the grounded or positive terminal of" battery.l

Relayl" n ovv` operates and inturn causes the operationo'f? relay IUli.V i

YThe subscriber now proceeds toy dial! andJ as the dialV returns tofnormal the dialing; loop-is intermittently'opened` and=closedl Y Upon the iirst opening ofthe dialing loop, current ceases to flow momentarily through `the primary winding P' of transformerl lll'- thereby producing surgesoff potential linthe secondary windings thereofwhich are opposite in directionv to the 'surges'rproduced" upon the closure of theI dialing loop. `The surge' in the secondary winding S* noW- decreases-theV positivepotential en thecontrol cathode of' the tube andthe surgein the secondary Winding S2 now decreases or substantially nullies the-'positive potentialV on the anode of the tube; The ionization of the tubecan'not `now be maintained and4 current ceases to flow over the cathodeanode circuit thro-ughv the winding of relay m3. Relay H33 releases but relayA |08'l being sloWto release does'not release and therefore an impulse is transmitted from ground over the back'contact oflrelay. IBB', front contact of relay 108? to the outpulsing circuit IDS.

On the next closure of the dial contacts, Vthe dialing loop is again-closed therebyfcausing theV v the intermittent release and'. operationof relay.,

As previously stated, since gaseousconductor tubes of..y the type disclosedy respond quickly to changesofipotential only and not to current build up' overthe dialing loop,..dialing or impulsing may bei accuratelycontrolled'over either long or short dialing loops and'atmuch greaterspeed. 'Further,V the impulse responsive relay such as |03 or'.v l03f neednot be of as sensitive a character or require asv iineanadjustment as Would be necessary were it to be operated directly by current impulses from the Vdialing loop as heretofore.

While YtheA invention has'beendisclosed inA connectionA withl a subscribers substation dialing loop, it Vwill'berobvious that it isequally applicable to. the; reception of. impulses generated in any desiredman'ner.

IVVhat' is claimed is:

`1. Ina signalingsystem,an impulsing circuit,Vv meansA for` closing said circuit, .a gaseous 'con-` gaseous conductor tube having a control electrode, a cathode and an anode, an inductiveconnectionlbetween said impulsing circuit and said anode;r means operative upon the closure of vsaid circuitiforlchangingthepotential on said control electrode, saidV anode being. simultaneously rendered' positive by theY surge 0f potential through said inductive-connection whereby said tube becomes conducting, and a,v cathode-anode circuit forsaid tube for maintaining saidtube in operationfollowing the' cessation of said surge, said anodebeing renderedless positive by the surge ofpotential in the oppositedirection through said inductivev connection incident to: thelopening of saiil'inipulsingl circuit to cause saidf tube to restor'e.-

'i 3; In a signaling system, an impulsing circuit, means for! closing said circuit, a gaseous conduttorA tubelhavingac'ontrol electrode, a cathode operative upon'i theclosureA of said circuit for changing the potentialon said control electrode,

said anodebelngl simultaneouslyrendered positiveby the surge of` potential through said inductive* connection whereby said tube becomes conducting-andi a=cathodeanode circuit for .said tubeinclu'ding- .a relay over which circuit. said tubeiand relayf are maintained operated following-the' cessation offsaidsurge,

4. In a signaling system, an impulsingcircuit,` irrean's for! ,closingI and opening saidV circuit, a gaseous-discharge lconductor. tube'having a control electrode, a cathodeA and an anode, an inductlve connection between said impulsing circuit and said: anode,V means operativeA upon the closure?. offsad' circuit for: changingV the potential on said control electrode, saidanode being simultaneouslyrendered positive by'the surge of potential through `said inductive connection. wherebyl'said: tubebecomes conducting, and a cathodetion of said tube and said relay.

5. In a signaling system, an impulsing circuit, means .for closing said circuit, a gaseous conductor tube having a control electrode, a cathode and an anode, a transformer having its primary winding connected tosaid circuit, a first of its secondary windings connected to said control electrode and a second of its secondary windings connected to said anode, said secondary windings being so poled with respect to said primary VWinding that upon the closure of said circuit the surges of potential through said secondary windings alter the potential on said control electrode and render said anode positive whereby said tube becomes conducting, and a cathode-'anode circuit for said tube for Imaintaining said tube in operation fcllowingthe cessation of said surges.

6. In a signaling system', an impulsing circuit, means for closing andv opening said circuit, a gaseous conductor tube having a control electrode, a cathode and an anode, atransformer having its primary winding connected to Vsaid circuit, a first of its secondary windings connected to said control electrode .and a second of its secondary windings connected to said anode, said secondary windings being so poled with respect to said primary winding thatupon the closure ofV said circuit the surges Vof potential throughtsaid secondary windings alter the potential on said control electrode and render said anode positive whereby said tube becomes conducting, and a cathode-anode circuit for said tube for maintaining said tube in operation following the cessation of said surges, the surges of potential in the Aopposite direction through said secondarywindings incident to the subsequent opening of said impulsing circuit altering the potential on said control electrode and renderingV said anode less positive whereby said tube restores to its normal condition.

7. In a signaling system, an impulsing circuit,` means for closing said circuit, a gaseous conductor tube having a control electrode, a cathode and an anode, a transformer having its primary winding connected to said circuit, a first of itsy secondary windings connected to said control electrode and a second of its secondary windings connected to said anode, said secondary windings being'so poled with respectto said primary winding that upon the'closure of said cir- Y cuit the surges of potential through said secondary windings alter the potential on said control ,electrode and rendersaid anode positive whereby said tube becomes conducting, and a cathode-anode circuit for said tube including-a relay over which circuit said tube and relay are maintained operated following the cessation of Y anca-264 closure ofv said' circuit the surges `ofy potential through said secondary windings alter the potential on said control electrode and render said anode positive whereby said tube becomes conducting, and a cathode-anode circuit for said tube including a relay over whichcircuit said tube and relay are maintained ,operated following the cessation of said surges, the surges of Y potential in the opposite direction through said secondary windings incident to the subsequent opening of said impulsingv circuit altering the potential on said' control electrode and rendering said anode less positive whereby said tube and relay are restored to their normal condition.

9. In a signaling system, an impulsing circuit,

means for closing said circuit, a gaseous discharge conductor tube having a control electrode, 1

a heated cathode and an anode, saidcontrol electrode having a normal negative bias, a transformer having its primary winding connected to said circuit, a first of its secondary windings connected to said controlA electrode and a Asecond of 4its secondary windings connected to said anode, said secondary windings being so poled with respect to said primary winding that upon the closure of said circuit the surges ofV potential through said secondary windings render said control electrode less negativeand said anode positive whereby said tube becomes conducting, and a cathode-anode circuit for said tube including a relay over which circuit said'tube and relay are maintained operated following the cessation of said surges. j

10. In a signaling system, an impulsing circuit, means for closing and opening said circuit, a gaseous'd-ischarge conductor tube having a control electrode, a heated cathode and an anode, said control electrode having a normal negative bias, a transformer having kits primary winding connected to said circuit, afirst of Yits secondary windings connected to said control electrode and V asecondV of its secondary windings connected to Vsaid anode, said secondary windings `being so poled with respect to said primary winding that Vupon the closure of said circuit the surges of potential through said secondary windings render saidcontrol electrode less negative and said anode positive whereby said tube becomes conducting,

and a cathode-anode circuit for said tube including a relay over which circuit said tube and recharge conductor tube having a cold control cathode, a second cold cathode and an. anode, said second cathode having a normal negative bias, a transformer having its primary winding connected to said circuit, a first of its'secondary windings connected to said c'ontrol'cathode and a second secondary winding connected to-said t anode, Vsaid secondary windings being so poledV with respect to said primary winding that upon the closure or said circuit the surges of potential through said secondary` windings render said control cathode and said anode positive whereby said tube .becomes conducting, and a cathodeanode circuit for said tube including a relay,

over'which circuit said tube and relay are maintained operated following the cessation of said surges.

12. In a signaling system, an impulsing circuit, means for closing and opening said circuit, a gaseous discharge conductor tube having a cold control cathode, a second cold cathode and an anode, said second cathode having a normal negative bias, a transformer having its primary winding connected to said circuit, a rst of its secondary windings connected to said control cathode and a second of its secondary windings connected to said anode, said secondary windings being so poled with respect to said primary winding that upon the closure of said circuit the surges of potential through said secondary windings render said control cathode and said anode positive whereby said tube becomes conducting, and a cathode-anode circuit for said tube including a relay over which circuit said tube and relay are maintained operated'following the cessation of vsaid surges, the surges of potential in the opposite direction through said secondary windings incident to the subsequent opening of said impulsing circuit rendering said control cathode negative and said anode less positive whereby said tube and relay are restored to their normal condition.

ROBERT O. SOFFEL. 

